The present invention relates to a clamp or closure for closing an open end of a drainable ostomy pouch. The invention is especially suitable for an integrally molded one-piece plastics clamp, but it is not limited exclusively to this.
An example of a conventional one-piece molded plastics clamp is described in U.S. Pat. No. 5,125,133, and is also shown in appended FIG. 1. The clamp consists of a thin wedge or blade member 10 receivable in the channel 12 of a narrow trough member 14 for clamping the outlet end of an ostomy pouch. One end of the blade member is hinged to a corresponding end of the trough member by an integral flexible hinge strap 16. The other end of the blade member is formed with a deformable cantilever lock 18 for forming a snap fit engagement with a lock keep 20 on the rough member.
The clamp is necessarily made of a relatively stiff, only slightly deformable plastics for optimum structural rigidity. Structural rigidity is important to ensure a tight clamping action, in order to prevent leakage of the pouch contents past the clamp. Such leakage would be highly embarrassing and unhygienic for the wearer. The comfort of the user is a secondary consideration in the above design. Also, in the above design of clamp, the blade member 10 and the trough member 14 are only coupled together at their ends. Since the clamp could be vulnerable to breakage or damage of the hinge strap 16, an additional guide 22 has to be provided on the blade member 10 at its end to prevent the blade member from falling out of the channel 12 were the hinge strap 16 accidentally to be broken in use.
Reference may also be made to U.S. Pat. No. 4,983,172, which describes another example of a one-piece clamp. This clamp is held in its closed position by means of lips located at the distal end of the channel or trough member, which snap over the top of the blade member when the blade member is pivoted to its closed position. The distal end of the blade member projects from the channel, and finger tabs are provide adjacent to the lips for applying pressure to open the clamp.
Broadly speaking, one aspect of the invention is to form at least one of the trough member and the blade member from integrally molded first and second plastics. The first plastics is relatively hard, and forms a first portion of the blade member and/or trough member. The second plastics is relatively deformable or soft, and forms a second portion of the blade member and/or trough member.
The first plastics can therefore provide structural rigidity for the clamp, to ensure reliable clamping action to avoid leakage of pouch contents. The second plastics can provide a soft or cushioned surface, to give the clamp a more comfortable feel to the user. This can improve user acceptance, and make the clamp more comfortable to wear.
In one form, both the blade member and the trough member include respective portions made of the first and second plastics material.
In another aspect, the invention relates to a method of integrally molding such a clamp with respective first and second portions of first and second plastics.
Another broad aspect of the invention is for the blade member and the trough member to be configured with inter-engaging profiles for forming an elongate mechanical interlock substantially along the channel of the trough member. In one form, the mechanical interlock is provided by an elongate constriction in the channel near to its mouth. This feature can also be used to create a seal between the layers of the pouch.
Another broad aspect of the invention is for the blade member to comprise a locking projection towards its distal end, for locking engagement with a portion of the trough member towards its distal end. The portion of the trough member may be located adjacent to the bottom (or floor) of the channel of the trough member. Therefore, instead of engaging only with a portion near the top or mouth of the channel as in the prior art, the locking projection can engage with a portion adjacent to the bottom of the channel.
The above aspects may be used independently, or advantageously in combination.
Advantages of the invention in its various aspects include: a softer exterior feel for the user, making the clamp more comfortable to wear; a more positive clamping action along the length of the clamp; and an alternative unlocking technique to the cantilever lock of the prior art. These and other features and advantages of the invention will become more apparent from the following description of a non-limiting embodiment of the invention.